In electric vehicles and hybrid vehicles, mounting a plurality of power storage devices and extending the distance (EV drive distance) that can be traveled without operating an engine has been contemplated. When the plurality of power storage devices are mounted in this manner, how electric power is distributed among the respective power storage devices becomes a problem.
Japanese Patent Laying-Open No. 2008-109840 discloses a power supply system for a vehicle provided with a plurality of power storage devices. In this power supply system, a discharge share ratio calculation unit calculates remaining electric power quantities of the respective power storage devices before a state of charge (SOC) with respect to which the allowable discharge electric power is restricted is reached, and calculates the discharge power share ratio between the power storage devices according to the ratio between the remaining electric power quantities.
A charge share ratio calculation unit calculates chargeable quantities of the respective power storage devices before SOC with respect to which the allowable charge electric power is restricted is reached, and calculates the charge power share ratio between the power storage devices according to the ratio between the chargeable quantities. When electric power is supplied from the power supply system to a drive force generation unit, a plurality of converters are controlled according to the discharge power share ratio. When electric power is supplied from the drive force generation unit to the power supply system, the plurality of converters are controlled according to the discharge power share ratio.    Patent Document 1: Japanese Patent Laying-Open No. 2008-109840    Patent Document 2: Japanese Patent Laying-Open No. 5-207668    Patent Document 3: Japanese Patent Laying-Open No. 6-253461